Computer systems configured as local area networks ("LANs") have been common for nearly two decades and are popular in a wide variety of business and educational applications. The most common LANs comprise a number of processing devices and a server that are coupled together by a hard-wired connection. Since about 1990, however, wireless LANs have become more common in the marketplace. Although the concept behind wireless LANS had been described a decade earlier, interest in LAN networks was limited until the release of the 2.4 GHz unlicensed band for industrial, scientific and medical ("ISM") applications. Wireless LAN products most often employ either direct sequence spread spectrum ("DSSS") or frequency-hopping spread spectrum ("FHSS") techniques to communicate between roaming mobile stations and network access points.
In a typical wireless computer network environment, the "backbone" of the LAN takes the form of one or more central servers that communicate with a number of network access points ("APs") through a hard-wired connection. Each AP includes a transceiver for communicating with at least one roaming mobile station ("MS"). The mobile station may be a point-of-sale terminal (e.g., an electronic cash register), a bar code reader or other scanning device, or a notepad, desktop or laptop computer. Each MS establishes a communication link with an AP by scanning the ISM band to find an available AP. Once a reliable link is established, the MS interacts with other mobile stations, a server or both. This allows the user of the MS to move freely in the office, factory, hospital or other facility where the wireless LAN is based, without the length of a hard-wired connection to the LAN limiting the movement of the MS user.
Many wireless LANs incorporate radio relays (functioning as repeaters) to relay messages from one mobile station to another mobile station (peer-to-peer traffic) or from a mobile station to an access point. This allows the communication link to be maintained even if the distance between the two communicating end-stations (whether mobile station or access point) is greater than the range of the transceiver of either or both devices. This also allows the communication link to be maintained even when a radio block obstructs the path between the two end-stations.
In most cases, however, a conventional radio relay blindly repeats any wireless message that it receives. This has the unfortunate drawback of consuming already limited radio bandwidth in those cases where the two end-stations that are communicating are within direct radio range of each other. In such a case, the repeated message is redundant and time-consuming. This situation is exacerbated when an end-station improperly receives the message, as when a redundancy check fails, and the receiver requests that the message be retransmitted. The radio relay repeats the retransmitted message, thereby consuming even more bandwidth.
Accordingly, there is needed in the art for systems and methods that selectively repeat transmitted messages in a wireless computer network only upon some indication that the destination end-station has not received a message. There exists a further need in the art for systems and methods that selectively repeat transmitted messages in a wireless computer network only upon an indication that the destination end-station has not received a message error-free.